A Dallas City Council committee wants new rail lines up and down and above and below Commerce Street.

The Mobility Solutions, Infrastructure and Sustainability Committee on Monday gave its thumbs-up to the proposed downtown Commerce Street subway alignment and a new streetcar line that would run along Elm and Commerce streets.

Plenty still has to be worked out. The full council still has to approve its preferred alignments. DART has to secure financing and grants. Operating and maintenance budgets are uncertain. And the plans could still be altered.

But after significant debate on the projects, the committee vote was "absolutely a step forward," said Kourtny Garrett, CEO of Downtown Dallas, Inc.

The long-debated $1.3 billion subway line will help Dallas Area Rapid Transit's entire rail system. Currently, all four lines — blue, green, orange and red — run through the same track downtown, which limits the frequency of trains and creates the potential for systemwide disruptions. The proposed subway would create new stops near DART's West Transfer center, the Perot Museum of Nature and Science and elsewhere downtown along Commerce.

The $92 million streetcar, meanwhile, would connect the existing streetcars that run through Uptown and from Union Station to the Bishop Arts District in North Oak Cliff.

Garrett believes the streetcar and the subway will serve a different group of riders. The streetcar will be available for short trips for those circulating only through downtown, Uptown and North Oak Cliff. The subway, she has said, is for commuters and people coming into downtown from other areas.

The streetcar is projected to be completed by 2023. The subway is scheduled for completion the following year.

But some of the council members wanted to see the streetcar farther away from the subway. Far North Dallas council member Sandy Greyson said she preferred the proposed streetcar alignment on Young Street, which would allow greater access to the Farmers Market area and possibly stimulate development in the vacant lots behind City Hall.

A streetcar on Commerce seems redundant, Greyson said.

"I don't understand why we would stack things on top of each other," Greyson said.

The council members decided to approve the Elm-Commerce alignment — a Downtown Dallas, Inc. study suggested it was the best option — but to also keep a Main Street alignment and the Young-Harwood alignment on the table if the finer details of the Elm-Commerce plans weren't workable.

The subway alignment went forward without much debate.

Council member Philip Kingston said he was "excited about this project" even though he was disappointed that DART had to take another crack at the alignment and delayed the subway's scheduled completion.